Eva Yearout, from the Barber County Z-Bar Ranch works to separate bison into pens Monday, Oct. 21, at the Tallgrass Prairie National Preserve near Strong City. Yearout, who helps manage a herd of bison at the Z-Bar Ranch, was on hand for the Tallgrass Prairie National Preserve's first round-up for weighing, tagging and drawing blood from their herd of 26 bison. .

Keith Yearout from the Barber County Z-Bar Ranch inspects the teeth of a bison, held still in a metal chute, Monday, Oct. 21, at the Tallgrass Prairie National Preserve near Strong City. Yearout, who is the ranch manager at the Barber County Z-Bar Ranch, where he cares for a herd of bison, was on hand for the Tallgrass Prairie National Preserve's first round-up for weighing, tagging and drawing blood from their herd of 26 bison. .

Veterinarian Drew Crisler with Jernigan's Veterniary Clinic, Council Grove, places a metal identification tag on the ear of a bison during the first round-up of the animals at the Tallgrass Prairie National Preserve in Chase County, Monday, Oct. 21, 2013. Twenty-six animals were weighed, tagged and inspected during the round-up. .

A crew of National Park employees, veterinarians, Nature Conservancy and state bison ranchers, work a herd of 26 bison, one at a time, through a special chute, where they can be weighed, tagged and inspected. The event took place Monday, Oct. 21, at the Tallgrass Prairie National Preserve near Strong City.

A National Park Service employee, top, counts bison still remaining in pens to be tagged and inspected Monday, Oct. 21, at the Tallgrass Prairie National Preserve near Strong City. Twenty-six of the park's bison were tagged and inspected.

Keith Yearout from the Barber County Z-Bar Ranch inspects a large bison, held still in a metal chute, Monday, Oct. 21, at the Tallgrass Prairie National Preserve near Strong City. Yearout, who is the ranch manager at the Barber County Z-Bar Ranch, where he cares for a herd of bison, was on hand for the Tallgrass Prairie National Preserve's first round-up for weighing, tagging and drawing blood from their herd of 26 bison, some topping 1500 pounds.